Vaginal specula, such as those that are manufactured and sold by Welch Allyn, Inc. of Skaneateles Falls, N.Y., among others are typically characterized by a pair of blade members that are inserted into the vaginal cavity of a patient. A blade articulation (angulation) mechanism is used to selectively vary the angular spacing or angular separation of the blade members to dilate the cavity for examination purposes. The upper blade member is pivotally attached to the speculum by means of a slide or yoke member wherein the blade articulation mechanism for these prior art specula typically includes a curved arm extending rearwardly from the slide member, the curved arm having a set of serrated ratchet teeth on a proximal side thereof that are engaged by an engagement tooth provided on a downwardly extending lever of the upper blade. The user pushes downwardly upon a tab portion of the lever in order to lock the upper blade member in a selected articulation (angulation) position wherein the angular separation of the blade members is required in order to suitably dilate the vaginal opening of a patient for examination purposes.
The above speculum can also include a similar ratchet mechanism which is provided on the slide member, and a downwardly extending handle portion of the speculum in order to provide vertical elevation (translation) adjustment of the upper blade member relative to the lower blade member.
One problem with presently known articulation mechanisms, as described above, is that the audible “clicking” sounds associated with the engagement tooth of the lever of the upper blade member and the serrated ratchet teeth of the member arm of the above specula can be unsettling to the patient. This problem can be distracting, and depending on the patient, traumatic in some instances.
Conversely, the audible clicking sounds produced by present speculum articulation mechanisms also provide a benefit for some physicians who are utilizing the apparatus in order to define a predetermined angular spacing, based on the number of audible clicks that are heard. As a result, there are reasons to provide an articulation mechanism that can selectively, but not necessarily, provide quieter operation, depending on the user.
Another problem that has been noted is that quite often a medical glove can become snagged or otherwise caught between the engaged teeth of the present articulation mechanism. This problem can cause tearing of the glove, creating a potential contamination issue, or can otherwise impair an examination. An additional problem that has been noted is that the predetermined number of discrete articulation positions may be limiting to the physician. In some instances, there may be a need to provide an articulation mechanism capable to being set to an unlimited number of possible positions, thereby enabling continuous operation. Articulation mechanisms are presently available to enable continuous operation, but none of these mechanisms enable selectivity by the user between discrete and continuous modes of operation. A further problem that has been noted is that the prior art specula do not allow articulation (angulation) without automatic locking of the mechanism. Some users prefer to control this articulation with one hand throughout the medical procedure being conducted.
It is therefore a general need in the field to provide a blade articulation system for a vaginal speculum that is reliable, but which is quieter in terms of its operation. It is yet another general desire to produce an articulation mechanism for a vaginal speculum that does not necessarily have to rely upon a predetermined number of discrete stops (i.e., articulation positions) for purposes of its operation, but rather can selectively perform continuously through an infinite number of positions over a specified range.